A decomposition technique to determine optimal coordinating policies of energy storage plants with electric power system

The problem of coordinating energy storage plants with an integrated hydroelectric power system to achieve minimum overall operating costs is a large and complex stochastic decision problem. This paper describes a decomposition technique which reduces the complexity of the problem and results in practical computational algorithms. The method is based on the definition of two subproblems. The first subproblem addresses the decision process for coordinating energy storage plants with an electric power system over a short period of time (for example, one day). This results in a functional relationship between the coordinated schedule and the parameters of the problem. Quadratic programming techniques are suitable for the solution of this subproblem. The second subproblem employs the above described functional relationship in order to define the optimal policy in coordinating energy storage plants over an indefinite time period of operation. Dynamic programming is employed for the solution of the second subproblem. Applications (pumped hydro storage stations, battery stations, etc.) are described. Results of a pumped hydro station application are cited.